What is the purpose of the Chi-square test?

To determine if the variation in collected data is due to chance or a specific variable being tested.

In the Chi-square formula, what do 'O' and 'E' represent?

Observed and Expected values, respectively

The null hypothesis states that there is no statistically significant difference between the observed values and the expected frequencies.

Degrees of freedom are calculated by subtracting 1 from the number of outcome categories (degrees of freedom = number of categories - 1).

It means you reject the null hypothesis, indicating there is a statistically significant difference between the observed and expected values.

I can apply the chi-square test to analyze observed and expected data.

1
The Chi-squared (χ²) test is used to determine if the variation in data is due to chance or a specific variable being tested.
2
The null hypothesis states there is no statistical difference between observed and expected values; this hypothesis is either accepted or rejected based on whether the calculated χ² value exceeds the critical value.
3
Degrees of freedom are calculated as the number of outcomes minus one, and the critical value is found on a chart, typically using a p-value of 0.05.